The inventive concept relates to a method for manufacturing a semiconductor and, more particularly, to a method for manufacturing an epitaxial semiconductor substrate such as a gallium nitride (GaN) substrate.
A gallium nitride (GaN)-based compound semiconductor corresponds to a direct transition type semiconductor. The GaN-based compound semiconductor may control wavelengths from a visible ray to an ultraviolet ray. Additionally, the GaN-based compound semiconductor may have excellent properties such as high thermal and chemical stability, high electron mobility, and high saturation electron speed as compared with conventional GaAs-based and InP-based compound semiconductors. Thus, the GaN-based compound semiconductor may be widely applied to various fields such as a light emitting diode (LED) of a visible ray region, an optic device (e.g., a laser diode), and electronic devices used in a next-generation wireless communication system and a satellite communication system which require high power and high frequency properties. In particular, a GaN semiconductor growth technique using a large caliber silicon substrate may realize low manufacture costs by mass production, application of a high level silicon semiconductor process technique, and integration with various semiconductors. Thus, various researches are being conducted for the GaN semiconductor growth technique, and the GaN semiconductor growth technique is in its early commercialization stages.
When a high-quality nitride semiconductor is grown on a (111) plane of a silicon substrate having a hexagonal system structure, a stress may occur within the GaN semiconductor by a difference between lattice constants and a difference between thermal expansion coefficients of the silicon substrate and the GaN semiconductor. Thus, a crack may occur in the GaN semiconductor. The crack occurring in the GaN semiconductor may function as a technical barrier in commercialization of optical and electronic devices using a silicon substrate. For resolving the problems, various researches are being conducted for various epitaxial structures and growth techniques.